Such devices are known and are, for example described in French Patent No. F-A 2 464 835. In the device described in this patent, the support is formed by several pairs of radiating rods (FIG. 8) each of which bears an anti-skid component at its outer end. The inner ends of the rods of each pair are connected to linking parts or flanges which connect them simultaneously to two jacks of a set of jacks disposed for example in a triangle. These jacks are actuated by the compressed air of the tire and are connected to the air valve of the tire by a flexible hose.
Such a device has two major drawbacks which have prevented its usd in practice. Firstly, the assembly of the components of this device does not form a rigid structure and its positioning on the tire of the vehicle without dismantling is long-drawn and arduous and necessitates more often than not the intervention of two persons. The regular positioning of the radiating rods proves, in practice, to be very difficult, if not impossible. Secondly, the anti-skid components have a tendency, upon the movement of the vehicle, to slip on the tread of the tire. This gives rise to a distrubance of the regular structure of the device and very often in the rupture of the flexible hose connecting the jacks to the air valve of the tire and thus in a complete detachment of the device.